Is that minute metal spot significant? More significant than the terrain and the fact that there is less area to defend? Your claim of more balance is not well supported and since it is a FFA it is not really important either.

Terrain imbalance is a whole other can of worms. East side may have more area to claim but the majority of hills are placed on the east side of map, allowing much easier and more effective porcing on east side. Most of this area is bordering the map, therefor only the front side facing opponents needs any defense. One can rush porc on the east hills which gives access to 6 standard mexes and 2 small mexes. It takes longer for north and south to reach these areas, and would likely have to fight for middle in order to obtain matching eco. East is not required to fight for mid for good eco, creating unfair competition.

I'm not sure why you would say balance is not important in FFA. Without more detail on that all I'm willing to say is that I disagree.

I much prefer this Desert Triad. FFA maps are not meant to be balanced in the same sense as balancing a team game. If one spot has a perceived advantage then the other players will just have to gang up on the more powerful player. Such asymmetries even help to start interesting conflicts between players as they misjudge what they can get away with.

A symmetrical FFA map has the risk that players will expand to their allotted mexes and defend. This results in a large stalemate.